Recurrent vaginal thrush: What to consider when thrush keeps coming back
What is vaginal thrush?
Vaginal thrush is known medically as Vulvovaginal Candidiasis (VVC), given the symptoms can impact both the vulva (fleshy skin on the outside of the vagina) and vagina (internal canal). Vaginal thrush is very common in women, with most experiencing it at least once in their lifetime, and although it can be experienced at any age, its most prevalent in our 20s and 30s.1
Vaginal thrush is caused by an overgrowth of candida, which is a yeast species. Yeast can be found in various parts of the body, and if low and controlled can be harmless, but if they increase in numbers, irritating symptoms can arise. The common strains of candida which are capable of causing vaginal thrush include candida albicans, nakaseomyces glabratus, candida parapsilosis and candida tropicalis, all of which we screen for in our Vaginal Microbiome Test.
What causes thrush?
Thrush tends to proliferate in warm, moist condition, and develops if there is a lack of good bacteria present.
Some of the main causes of thrush include:
Antibiotic use - these medications reduce the good bacteria that are protective against yeast overgrowth.
Lifestyle practices - that disrupt the protective microbiome of the vagina may cause yeast e.g. tight clothing, chemicals in personal products.
Hormone imbalances - high levels of oestrogen can cause yeast to proliferate, so the OCP or HRT can trigger thrush, or conditions associated with oestrogen dominance such as Endometriosis and Polycystic Ovary Syndrome (PCOS).
A weakened immune system - as a result of an illness or immune suppressant medications.
Poorly controlled diabetes - high blood sugar levels can cause yeast to proliferate
Pregnancy - due to changing hormones
Partners - can also share microbes, including yeast. It is a good idea to check your partner for symptoms in cases of chronic yeast infections.
What is defined as chronic thrush?
Recurrent Vulvovaginal Candidiasis (rVVC) occurs when a woman has 3-4 episodes or more in a year, and the repeat infections are not linked to antibiotics.
Chronic vaginal thrush presents as: white discharge, itching, dryness, sore inflamed skin, in some cases there may be a white film over the affected area, and possibly painful sex and urination.
Women may experience some relief during their bleeds as yeast is flushed out, and the pH of the affected tissues becomes less acidic. But generally symptoms become persistent and can impact one’s quality of life significantly.
Why does thrush become so stubborn in some women?
Thrush can be stubborn for many reasons: treatment doesn’t work effectively, candida strains can become more pathogenic over time, candida produce protective biofilms and ongoing systemic drivers continue to fuel yeast growth. In many cases the causes are likely a combination of these:
1. Treatment issues
Antimicrobial resistance is an increasing problem with the candida strains so in some cases the overgrowth will not reduce with treatment .1 Moreover, when anti- fungal treatment is prescribed, its often not known what type of yeast is present, so on occasion the anti fungal may not be appropriate, allowing yeast infections to continue.
2. Yeast strains become more pathogenic over time
Candida albicans in particular, can become more pathogenic over time, due to its ability to form long filamentous hyphae, able to invade and damage mucosal epithelial cells, causing ongoing tissue damage and discomfort.2
3. Biofilm formation
Candida species are able to produce biofilms, a physical layer of extracellular defence, which protects them from external factors such as our immune system and anti-fungal drugs, which would normally prevent persistent growth.3
4. Ongoing systemic drivers
The reason thrush continues to be a problem for many women is that systemic drivers of yeast are not being addressed. Addressing these should be one part of a plan to support women with chronic yeast overgrowth.
Balance oestrogen levels - too much oestrogen in the body can drive yeast overgrowth. Balance oestrogen levels by including fibre in the diet, staying regular and eating cruciferous veg and broccoli sprouts often. Seek further guidance if needed.
Balance blood sugar levels - blood sugar spikes from sugary foods can cause many issues for the body, including yeast overgrowth. Balance blood sugar levels by reducing or ideally avoiding processed foods, eating three balanced meals per day with protein at every meal, making healthy swaps including dark chocolate instead of milk chocolate, honey instead of sugar on porridge, liquorice tea instead of a cookie.
Reduce overall inflammation - systemic inflammation can aggravate symptoms in an already inflamed environment. Support skin health by eating oily fish (salmon, mackerel, anchovies, sardines), chia seeds and walnuts, and enjoy anti inflammatory foods such as berries, spices, olive oil, fruits and vegetables.
Support gut health to strengthen the immune system - gut dysbiosis (imbalance) can negatively impact the immune system and microbiome of the vaginal canal. Nurture the gut with fibrous foods (fruit, veg, lentils, peas, beans), probiotic foods (sauerkraut, kimchi, kefir), and prebiotic foods (oats, bananas, leeks, artichoke).
Address the bacterial microbiome of the vagina - a lack of protective lactobacillus will increase the risk of opportunistic yeast overgrowth in the vagina. Ideally find out your vaginal microbiome scores, via out test, and optimise the healthy bacteria lactobacillus if needed.
Address partner sharing - yeast can be passed to a female from a male, if yeast is present on penile skin or in the seminal fluid. If a male has symptoms, recommend treatment. Adoption of an anti inflammatory diet, with plenty of herbs and spices, can assist.
Keep fighting to get the right treatment and support
If you have chronic yeast infections and symptoms, please see a medical professional. Ensure other diagnoses have been ruled out too such as BV or skin conditions.
Addressing chronic yeast infections can involve a multifaceted approach, including diet, lifestyle, correct medications and persistence.
A private microbiome test can tell you the exact yeast strain causing the infection, which can facilitate targeted medication which may be key insight in some cases.
References
1. BUPA. Vaginal Thrush. Available at: https://www.bupa.co.uk/health-information/womens-health/vaginal-thrush. Last accessed July 2025.
2. CDC. Candidiasis - Antimicrobial-Resistant Invasive Candidiasis. Available at: https://www.cdc.gov/candidiasis/antimicrobial-resistance/index.html. Last accessed July 2025.
3. Chen H, Zhou X, Ren B, Cheng L. The regulation of hyphae growth in Candida albicans. Virulence. 2020 Dec;11(1):337-348.
